Engine Sump Air Separation via Windage-Suppressor Shroud
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Solution Overview
Problem
In gas turbine engines, the mixing of oil with high-pressure gases in the sump cavity disrupts the lubrication system, leading to inefficient lubricant distribution and potential oil loss through vent passageways, which complicates the management of air and oil flows.
Innovation Solution
An annular windage-suppressor shroud is designed to direct high-pressure gases from the seal gap into a vent passageway while preventing oil from mixing with these gases, using a guide passageway with radially-inwardly opening inlet and outlet, and guide vanes to ensure efficient air routing without oil entrainment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If high-pressure gases are allowed to mix with oil in the sump cavity, then the gases can be vented through the vent passageway, but oil is entrained and lost through the vents
Solution Approach 1:
The sump cavity is segmented into distinct zones using a baffle structure that separates the gas flow path from the oil reservoir. The baffle creates a first region for gas venting and a second region for oil collection, preventing mixing while maintaining simple overall structure
Solution Approach 2:
The high-pressure gases are extracted and directed through a dedicated guide passageway that bypasses the oil-containing region. The guide passageway with guide vanes channels gases directly to the vent passageway outlet, removing them from the sump cavity before they can entrain oil
2Productivity
If the breather size is increased to handle air flow, then air handling capacity is improved, but the device size and weight increase
Solution Approach 1:
Guide vanes are introduced as intermediary elements within the guide passageway to actively direct and control the high-pressure gas flow. These vanes streamline the gas path, improving flow efficiency and reducing the required breather size while maintaining effective air handling capacity
Solution Approach 2:
The system changes the flow parameters by using guide vanes to optimize gas velocity and direction within the guide passageway. This controlled flow management allows for more efficient air handling with reduced component sizing
3Productivity
If guide vanes are added to direct high-pressure gases, then air routing efficiency is improved, but device complexity increases
Solution Approach 1:
The guide vanes are designed with specific geometric parameters including span, chord length, and twist distribution that optimize gas flow dynamics. The vanes create controlled flow patterns that efficiently direct high-pressure gases through the guide passageway while maintaining manageable structural complexity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively minimizes oil carried out through vents, allowing for efficient air handling and reduced breather size, maintaining oil distribution to bearings and reducing the risk of oil loss, thus optimizing the lubrication system's performance.
Implementation Method 1
The annular windage-suppressor shroud is located in the sump cavity and arranged circumferentially around the shaft assembly to direct the high-pressure gasses from the outlet of the seal gap to the vent passageway
Implementation Method 2
The plurality of guide vanes may extend radially between the inner wall and the outer wall to direct the high-pressure gasses from the guide inlet toward the guide outlet
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A sump assembly for use in a gas turbine engine includes a housing and a shaft assembly. The housing is arranged about a central axis of the sump assembly to define a cavity configured to house oil and high-pressure gasses. The shaft assembly is mounted to rotate about the central axis and to direct the high-pressure gasses into the housing.